1. Field of the Invention
This invention relates to locking systems in general, and specifically to a locking arrangement to secure gate valves against tampering.
2. Description of the Prior Art
Gate valves have long been, and are today, extensively used to control the flow of fluids frequently under high pressure. Among such uses for gate valves would be controlling the flow through pipes of steam, oil, water, gas, and other fluids. Such valves are used at selected points on pipelines, in plants and to control the flow of water into buildings and other facilities. It is generally most desirable to secure a gate valve which is being used in a preset position and, for this purpose, the wheel of the gate valve is often secured to the truss support or other stationary portion of the valve by means of a chain and padlock. Unfortunately, it seems to have been a great temptation to certain people, or even organizations, to tamper with the settings of gate valves and to do so, the chain may be cut or the staple of a padlock may be sawed. Quite frequently, tampering with a gate valve to the extent of changing its setting, even to the point of shutting it off completely, or opening a valve wide may produce disastrous consequences. For example, if the flow of water to a building should be shut off, none of its automatic sprinklers may work with the result that there would be no automatic suppression of a fire which may be started in any of the building offices. In the situation of a pipeline conducting the flow of oil or water, shutting a gate valve may result in shutting down pumps or even damage to pumps which are not provided with means to respond to a stoppage of the fluid flow. In recently filed patent application of the present invention, Ser. No. 08/020,197, there is illustrated and described a use of the novel lock of that application to an arrangement for locking a gate valve. The embodiment shown in that application, however, would require welding of a lock to the bonnet or ring securing the bonnet of the valve.